To offer a different perspective than Cognovi, there are actually a lot of radiologists who say that the prestige of where you attend matters zilch. Whether this is true or not is hard to ascertain as I imagine despite their best efforts, even THEY have a subconscious bias that goes “oooh, Stanford”, and additionally it’s hard to think that someone attending a top 20 would be viewed the same as someone attending a community program, all other things being equal. All other things are very rarely ever equal, though, and it may be that someone coming from a top 20 may be picked second to someone from a local community program whose attendings regard them very highly, and communicate that regard to local practices who know those attendings very well.
Prestigious name brand is more important if you have to sell your name to someone. IR is likely to weigh this more heavily as they are more patient-facing, and depending if their practice is set up this way, they are more likely to draw patients to their practice if they have more top-tier trained radiologists.
Diagnostic radiologists are in the position (lucky or unlucky) that they usually DON’T have to sell their name to someone, except maybe an employer who is trying to recruit as prestigious a faculty lineup as possible (major national cancer centers like Sloan, MD Anderson, etc; as well as top tier academic institutions). Generally though the average private practice who serves one or a few hospitals in a pseudo-academic or community setting doesn’t care much about where their radiologists train. They want radiologists that can cut through the list quickly and accurately, and while prestige of training has some bearing on that, the best way to assess this is in the early pre-partner, employed period.
TLDR - sometimes it matters, sometimes it doesn’t, it depends on what you want to do with your life and who you’re asking.
Attending a weaker residency program can be made up by attending a prestigious fellowship near where you want to work if you want to go to PP, or attending a fellowship that does very good, cutting-edge academic work in the sub-specialty you want to go to (but you have to think about this functionally. E.g. if you want to do the basic sciences behind tracer kinetic modeling, Yale > UCSF who is much more robust clinically, although both do great nucs research. Academics is all about the niches of subspecialties, and if you want to do that you have to pick your niche, find the people who are on all the papers in that niche, and go to where they are).